McArthur will serve as the Royals' opening pitcher for Wednesday's game versus Seattle, Anne Rogers of MLB.com reports.
McArthur will be making the first start of his major-league career Wednesday. The 26-year-old righty has allowed two runs over four innings since being recalled from Triple-A Omaha on Aug. 4. He'll likely pitch for an inning or two before turning the game over to the bullpen, with Alec Marsh likely to serve as the Royals' primary pitcher.